264 MAZATLAN 'tTKITALYES 



adopted from tlieir great convenience. Of Calyptrsca proper, 

 which is the best marked in its characters and is -well repre- 

 sented both in individuals and species in the Caribbsean and 

 equatorial West American Seas, only a single individual -svaa 

 found in the entire Mazatlan collection. None of the species 

 were found with a solid shelly attachment, though a thin 

 deposit may sometimes perhaps be traced. In general a cavity 

 is excavated on the backs of other shells. 



Family C.iLYPTE.'HID^. 

 Geijus TEOCHITA, Schnm. 



Schum. Ess. no. 11, 1815. — Gray, Proc. Zool. Soc. 1847, p. 158, 



no. 2T2.—Phil. Eandh. Conch, p. 187.— -ff. Sf A. Ad. Gen. i. 



867. 

 Trochus, pars. Lam. — Calypti'sea, pars. Desk. Sigapatella, Less, 



1829, Voy. Co(7.— Trochatella, Less. 1830, (teste Gray.J—Jn- 



fundibulvim, B'Orb. 1816, non Mo?iff. 



This genus forms an exact transition in the shell from the 

 spiral Crepidula) to the Phorida^, the animal of; which is 

 widely different. It is in fact a Crcpidula, with the anterior 

 part shortened, while the posterior is lengthened. Several 

 species might be ranked with either genus. It is represented 

 in the Llazatlan collection by a single specimen. 



331. Teochita ventkicosa, 7i. s. 



T. i. ventricosa, suhdepressd, irrerjulari ; alhidd, castaneo 

 tmhuta : anfractibus m. \^? aut plurihus~\ ventricosis, maxime 

 prope suUcram ad ang. 90° depressam ; superjie'ie i rregulariter 

 noduloso-rugosd, rugis subobsoleiis, diagonalibus, noduUs hue et 

 illuc prope siduram extajdibus ; iota pagind creberrime et 

 minutissime corrugatd ; epidermide lamellosd, corned, maxime 

 prope ihargincm, indutd ; cavitate coneavo ; lamina albd, lineas 

 incrementi hand monstranti, labia parum reflexo, umbilieo nullo; 

 margineformcc sedis convenicnte. 



Corap. Trochita radians, (Desh. teste H. Sf A. Ad. Gen. i. 367,) 

 Dkr. Ind. Moll. Guin. p. 36, no. 97:=Troehu3 r. Lam. An. 

 s. Vert. (ed. I.) vol. vii. p. 11, no. 5 : — Schnb. ^' Wagn. 

 Chemn. Suppl. pi. *^9, f 4063 :— = Calyptja^a r. Zaw. ed. 

 Desh. vol. vii. p. 626, no. 8 : — = luf undibulum r. Zool. Pecch. 

 Voy. p. 1<18, pi. 39, f. 10, 11 :—= Patella trochiformis, Chemn. 



